20-HETE mediates Ang II-induced cardiac hypertrophy via ROS and Ca2+ signaling in H9c2 cells.

In the vascular system, angiotensin II (Ang II) mediated vasoconstriction by inducing the production of 20-hydroxyeicosatetraenoic acid (20-HETE). However, the role of 20-HETE in Ang II-induced cardiac dysfunction had yet to be fully elucidated. This study investigated the effects of Ang II on CYP4A expression and 20-HETE production in H9c2 cells using RT-qPCR, Western blot, and ELISA. The role of 20-HETE in Ang II-induced cardiac hypertrophy was examined using DHE, MitoSOX, and JC-1 staining to evaluate reactive oxygen species (ROS) generation and mitochondrial membrane potential changes. The ERK/Akt and CaN/NFAT3 signaling pathways were analyzed through Western blot. Ang II was found to promote CYP4A expression and 20-HETE production in H9c2 cells via an AT1 receptor-dependent mechanism. Additionally, the upregulation of AT1 receptor expression by 20-HETE further confirms its facilitatory effect on the Ang II signaling pathway. Inhibition of 20-HETE synthesis or blockade of its receptor, G-protein-coupled receptor 75 (GPR75), significantly reversed Ang II-induced cardiac hypertrophy. This reversal was closely associated with 20-HETE-induced ROS production, oxidative stress, and activation of the Ca2+/CaN/NFAT3 signaling pathway. This study demonstrated that 20-HETE mediated Ang II-induced cardiac hypertrophy and, for the first time, highlighted the significant role of the GPR75 receptor in this process. These findings suggested that targeting 20-HETE reduction or blocking its receptor action could offer a novel therapeutic approach for cardiovascular diseases associated with Ang II.